FBL Head setup

[Pinecone]

And if you run 8717s you need to Dremel out the other side to prevent the servo case from rubbing and transmitting vibration from the frame to the servo.

I won't get into which side the collective servo should be mounted.

[flymustangs]

This is making me rethink my decision to go with the 8717's

[cbergen]

I have the 8717's in my 44 Magnum, it's a NO problem...

If you feel the need, cut into the round corners, squaring them off to better fit the servo.

[Pinecone]

No problem and they fly great.

I found that to get a good clearance, I needed to file the holes a bit, not a huge amount.

I was more agressive on the otehr frame opposite the collective servo to make sure it didn't touch.

[cbergen]

Videos added, one of the Tazer with FBL head..Just some testing we did last winter, but kind of cool...

http://bergenrc.com/Videos.php?&page=2

[LITHIUMSTATIC]

[ltdorn]

I finished my new FBL standard gasser with 710 NHPs and hanson 3d max.

Sorry maybe i missed it, but what RPM do we run with the FBL?

[cbergen]

The same RPM as with Flybar, 1450-1500 for normal mode hovering, but for doing aerobatics go ahead and bump it up to 1850-1900.

[ltdorn]

Another setup question

so now that shes all together, today i tried some limited 3d. and got some weird interations so i tried to lock them all down..

When trimmed out in a nice stable hover with little to no wind i get the following.

1. When i put in only right aileron i get a forward interaction and it goes right and forward.
2. When i put in only left aileron i get a backward interaction and it goes left and back
3. When in forward flight it pitches up with any forward speed, (upwind or downwind and with no wind)
(if i come off forward stick it will pitch up and slow almost to a stop.)

a. were is the CG supposed to be? i have two batteries up front for weight. Only using one of them for power though. I did a CG check and the rear skids lift off to about 1/4 inch before the forward skids come off.

b. I did set the timing up like in the instructions, i even tried moving the timing a bit forward and back to check if this was the problem but the interactions remain, at least i cant see a big difference.

Any suggestions as my little 500 electric exhibits non of these symptoms, it tracks like an arrow in all directions and doesn't pitch up at all up wind or downwind. I fly with Thumb and index finger and was making sure i was only putting in put left or right inputs.

[cbdane]

Originally Posted by ltdorn

1. When i put in only right aileron i get a forward interaction and it goes right and forward.
2. When i put in only left aileron i get a backward interaction and it goes left and back

This sounds like a phasing error. Here's a good test that I learned from MrMel (FBL guru here on HeliFreak). Start with the heli with a tail-in steady hover. Now do a quick back-flip to nose-in inverted hover using pure elevator stick. If the tail is not directly lined up, parallel to the starting point, it could be phasing or a tail-hold problem. Now, flip it back to right-side-up with another back-flip in the same direction. If the tail comes back to correct alignment, the problem was phasing. If it is rotated to one side, then the problem is tail control.

To check elevator phasing (pitch), place the blades exactly parallel with the tail boom. Now, input elevator commands and make sure that you see no motion in the blades. If you see a small change in pitch, make rotational adjustments to the swash driver until you can move the elevator stick with no blade motion.

3. When in forward flight it pitches up with any forward speed, (upwind or downwind and with no wind)
(if i come off forward stick it will pitch up and slow almost to a stop.)

This can be a characteristic of a flybarless head with no electronic correction. One suggestion that I've heard from the scale guys who aren't running flybarless electronics is to set up the heli slightly nose heavy. I have a 5-blade flybarless and it has very strong nose-up tendencies in forward flight but 2-blade heads are usually less of a problem. Chris and others are flying no-electronics quite successfully.

By the way, the heli doesn't know anything about "downwind" or "upwind" since it is flying in a moving mass of air that, to its frame of reference, looks stationary. The flight characteristics should be the same in both cases. The one thing that can happen to make them appear to be different is that if you try to maintain the same ground speed in each direction, effectively giving the heli a higher airspeed in the upwind direction.

Just some thoughts based on my experience with FBL.

[cbergen]

What was your headspeed?

Verify that there is no interaction in the servos. Look at the ail servo while movign the ele cleanly fore and aft, and vise versa, look at the ele servo while moving pure ail side to side.

Feel free to adjust the timing as far as necessary to eliminate the interaction in flight, but only after verifying the servos are not interacting...

[ltdorn]

Hi,

i am running 1900-1950 W/o governor on you recommendations.

I will try the blades for and aft and look for interations and also make sure the are interactions with any of the servos.

Didn't realize that FBL heads pitch up on forward flight.

let you know tomorrow after flying.

[cbergen]

FBL does tend to Balloon up in FFF, but it should not be anything drastic or sudden.

The new blades from EDGE that are designed for FBL applications make a great difference in this as well. I hope to have some 713 mm blades here soon for testing on the Gasser, we'll see how they compare to the Radix 710mm Blades I'm currently using.

[cbdane]

Originally Posted by cbergen

FBL does tend to Balloon up in FFF, but it should not be anything drastic or sudden.

The new blades from EDGE that are designed for FBL applications make a great difference in this as well. I hope to have some 713 mm blades here soon for testing on the Gasser, we'll see how they compare to the Radix 710mm Blades I'm currently using.

That sounds very interesting.

[flymustangs]

I have thew Edge 693 flybarless blades on the Tazer and they seem to do well. That's the only blades I've had on there so I can't make a comparison.

I've also used the Edge blades on a TREX 600N when I converted it to vbar. They seemed to do better than the CY blades that were on there, but that was also with a flybar.

[ltdorn]

Ok ... did a little tweaking today....

used a laser level to line up all the balls on the swash and blade grips so they were all in a line just like the instructions say too.

since i cant do a "a quick back-flip to nose-in inverted hover using pure elevator stick." lol

I att it on the ground and run up and get light then apply pure forward stick and see how the disk titled. Disk titled forward and to the left. I had to change my timing to the right (CW) abit to remove the left tilt.

I also swapped out my NHP's for a set v blades. i think there was more pitch up with the vblades.

Added about -10% expo from 0 expo. that smoothed it out a lot.

Waiting for the report on the Edge 713!

[cbergen]

Expo,

I started with about 20-25% expo, but have it down to 10% on my gasser, IIRC..The Tazer still has a bit more expo, but being lighter it is more "manueverable"...

[Magenta]

Originally Posted by ltdorn

used a laser level to line up all the balls on the swash and blade grips so they were all in a line just like the instructions say too.

That's a great idea. I'll have to try that

[ltdorn]

Yea... its one of those craftsman laser levels that projects the straight laser line either Horizontal or vertical for putting up pictures and such.

Expo.... I read your post in the flybarless forum and saw you used -10, so i used -10 and its about perfect....well i like it...

[cbergen]

Futaba or JR?